1. Field of Invention
The present invention relates to a positioning structure of a clean container. More particularly, the present invention relates to a positioning structure, applicable in a clean container for elastically pushing against and positioning a plate made of a brittle material.
2. Related Art
For a common clean container, regardless of a mask box, a reticle box, a wafer box, or a glass substrate box, a mask, a wafer, a reticle, or a glass substrate is usually accommodated therein. However, the mask, the reticle, the wafer, or the glass substrate has an extremely high requirement on the ultra-clean storage environment. For example, the current semiconductor fabricating process requires the environmental quality to reach a level above Class 1, so that the contamination caused by fine particles and the effect of the electrostatic charges or the electrostatic field must be strictly prevented. Therefore, in a semiconductor or flat-panel display manufacturing process, a mask, a reticle, a wafer, or a glass substrate should be performed in an ultra-clean environment without particles. The clean container plays an important role as an environment meeting the clean requirements in the process for fabricating semiconductors or flat panel displays, so as to ensure the mask, reticle, wafer, or glass substrate to be kept in an environment meeting the clean requirements when being transported, detached, and stored.
As disclosed in U.S. Patent Publication No. 2004/0004704, referring to FIGS. 1A, 1B, 2A to 2D, FIG. 1A is a sectional top view of a mask box in the prior art; FIG. 1B is a schematic sectional diagram of FIG. 1 obtained along the line A-A; and FIGS. 2A to 2D are schematic diagrams of the motion of rigidly pushing against the mask box in the prior art. Taking the reticle box as an example, the reticle accommodated therein must be positioned on the base of the reticle box, so as to avoid the friction caused by the movement of the reticle in the reticle box when the reticle is transported, detached, and stored. According to a conventional method, the base 10 of the reticle box has a baffle 11 disposed on the upper surface for positioning the reticle 14, and has a guide rib 13 formed on the upper cover 12 of the reticle box, and an inclined plane 131 formed on the guide rib 13. Afterwards, the reticle 14 in the reticle box is pushed by utilizing the inclined plane 131, such that the reticle presses against the baffle 11, thereby positioning the reticle 14. However, the inclined plane 131 in the prior art is not designed with an elastic property, and it will directly press against the reticle 14, so when the reticle 14 in the reticle box is pushed by the inclined plane 131, it is extremely likely to generate fine particles and electrostatic charges due to direct and rigid crashing, contacting, and friction, thereby causing a contamination to the reticle 14.
Furthermore, the above conventional inclined plane is not designed with an electrical conductive property, so that the electrostatic charges of the reticle cannot be conducted out of the reticle box.